Pipe hangers for suspending plastic or metal pipes substantially horizontally from support structure such as a wall or an underfloor joist are well known. Such hangers are used for a variety of piping applications in residential and commercial buildings and plants including supply lines, such as water and natural gas supply lines, drain and sewer lines, conduit, etc. Two types of pipe hangers are in common use: strap type pipe hangers and hook type pipe hangers. Strap type pipe hangers typically include a stem with a plurality of openings for attachment of the pipe hanger to a joist using nails, screws or other fasteners and a strap extending from the stem and having a ratchet structure for holding a pipe. Patents disclosing strap type pipe hangers include U.S. Pat. No. 4,768,741 to Logsdon and U.S. Pat. No. 5,746,401 to Condon.
Hook shaped pipe hangers typically include a stem with a plurality of openings for attachment of the pipe hanger to a joist and a rigid hook portion for supporting or cradling a pipe. Patents disclosing hook type pipe hangers include U.S. Pat. No. 4,407,478 to Hodges, U.S. Pat. No. 5,542,631 to Bruno and U.S. Pat. No. 5,385,320 to Ismert et al. Since the size of the hook of hook shaped pipe hangers is fixed, such hangers require offering a variety of pipe hangers with different size hook portions to accommodate different size pipe outer diameters. However, hook type pipe hangers facilitate installation of pipe by one person because the hook supports a pipe section while pipe sections are being coupled together. By comparison, strap type pipe hangers require two hands for installation as the pipe section must be supported while the strap is being tightened. Moreover, strap type pipe hangers provide a less appealing visual appearance.
One deficiency of hook type pipe hangers is that the pipe is only supported along a lower half or peripheral circumference of the pipe and the upper half of the pipe is unsecured. Thus, the pipe is susceptible to being raised or lifted out of the hook portion and thereby dislodged from the pipe hanger. This is especially problematic if the pipe hanger is not mounted vertically upright but rather at some other angle. For example, if because of spacing considerations, it was desired to hang the pipe hanger upside down, a simple hook type pipe hanger could not be used because the pipe would not be supported by the pipe hanger. Additionally, even if the hook type pipe hanger is mounted in an upright position, since an upper half of the pipe is unsecured, the pipe is prone to vibrate as pressure fluctuations occur in liquid or gas passing through the pipe, for example, vibration may occur in water supply pipes when a valve is turned on or off or from a water hammer effect.
Attempts have been made to provide additional securement of the pipe within the hook portion and additionally allow the pipe hanger to be used in an inverted position, if desired. Both the '478 patent to Hodges and the '320 patent to Ismert et al. contemplate a protrusion or tooth extending from the stem which provides a snap-fit engagement with the pipe. This approach, however, only secures a portion of the upper half of the pipe. Under conditions of strong vibration of the pipe or if the pipe hanger is used in an inverted position, there is a likelihood of the pipe snapping over the tooth and becoming dislodged from the hanger.
The '320 patent to Ismert et al. also discloses a cable or strap tie which is threaded through slots in the stem and the tip of the hook portion to provide additional securement of the upper half of the pipe. However, threading the cable tie through the narrow slots would be time consuming and difficult especially in situations where the pipe hanger is in a position that is difficult to access or poorly lit. Moreover, the cable tie could not be preinstalled prior to insertion of the pipe because the nonconnector side of strap tie would be pushed downwardly under the pipe. Additionally, when tightening the cable tie, the longitudinal force of the cable tie is directed to the hook tip and the stem adjacent the slots and only a smaller tangent force is applied against the pipe outer surface. Thus, the force applied by the cable tie upon tightening is directed to deflecting (and potentially breaking) the hook tip while only incidentally applying a radially inward and downward force on an outer periphery of the upper half of the pipe.
What is needed is a hook shaped pipe hanger that includes structure to secure an upper half of a pipe against the hook portion by applying a radially inward and downward force on an outer periphery of the upper half of the pipe and which is pre-installed or integral to pipe hanger. What is also needed is a hook shaped pipe hanger that is easy to install and easy to secure the pipe within the hook portion. What is also needed is a hook shaped pipe hanger that is cost efficient to manufacture.